#include <iostream>

using namespace std;

int main()
{
    int niza[5];
    int zbir = 0;
    for (int i = 0; i <= 4; i += 1)
    {
        cin >> niza[i];
        zbir += niza[i] /= 2;
    }
    cout << zbir << endl;
    return 0;
}